Underneath is a Deaver leaf-sprung rear 14-bolt fed from an NP205 transfer case bolted to an SM465 four-speed manual transmission. But noteworthy are a few weight-saving measures done to boost the power-to-weight ratio of the old GMC. The heavy rear drums were swapped out and replaced with a disc-brake kit from Sky Manufacturing, and the rusty floor was replaced with a steel grate, making a giant storage basket without adding weight.